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Re: Solar Gain Tests

"Consequently, of the black wraps, roofing paper will show the highest temp spikes and the fastest temp changes, dropping down to ambient the fastest once the sun goes down."

True for an empty hive. Mass (bees, honey, frames, wax, etc.) will act as a heat sink and absorb the heat throughout the day and throw off heat during the dark hours.
Thanks again for the tests.

I agree, but the general affect will still be the same - more insulation means smaller spikes and more gradual changes; less insulation means higher spikes and faster changes. Internal thermal mass and bees' heat will serve to smooth the temp cycling in each situation. Also, the larger a colony, the more heat provided by bee heat, and, consequently, the less the proportional contribution of solar gain to the internal temp of the hive.

Re: Solar Gain Tests

Originally Posted by Barry

What are they to you? It tells me that all the wrapping doesn't make much of a difference. At the end of the day, they equalize out.

Since you asked, to me, it clearly shows a heat gain during the day. You are correct however at the END of the day they equalize out in this spcific test.
I'm more interested in the heat gain that may or may not carry the bees through a cold night (like last night) in a real world application.

Re: Solar Gain Tests

Whatever the thermometers say, and the theorists say….

I keep bees where is stays cold all winter and some years there are no cleansing flights. I've seen the weather conditions almost but not warm enough for a good flight, and because the micro-climate around the hives is warmed enough by the black paper, the bees are able to take a cleansing flight…remaining within a few feet of the hive, cleanse, and flying back into the hive. Many will cling to the black paper…warming up enough to fly.

Wrapping probably doesn't help every year, but when it does, it does. I can install a wrap in a minute, and remove quicker than that. So, I figure, whether it helps a little or a lot, it's worth doing where I keep bees.

Re: Solar Gain Tests

The mass of wax, wood, and honey would obviously absorb heat and contribute to the "warmth" of the hive's interior.

Even without the heat sink effect of the interior's mass, a rise in temperature during the day would allow more movement, possibly permitting the cluster to move to that frame of honey that is often out of reach.

An increase in temperature for whatever length of time will reduce the amount of honey consumption and that will be helpful in getting the bees through the night....

Re: Solar Gain Tests

A couple of thoughts....

1. The winter thermodynamics of a hive is complicated in the extreme. In addition to what has been mentioned, the bees do create airflow and I'm not sure how much the cluster is helped by raising the ambient temp in the air around the cluster...certainly it isn't universally beneficial.

2. I've been doing some similar experiments (no details yet) and settled on using a mocrocontroller (arduino ) and some little devices that look like small transistors but are really digital temp sensors. These are built on the onewire protocol... one lead is ground, one is an optional power supply (they work better if you give them power) and one is a data line.
The data line can also provide parasitic power, but each sensor has a digital address, and can be read individually.....even though they share a data bus (hence the onewire name).
They are accurate and relatively inexpensive.

Deknow

Sometimes the lights all shining on me
Other times I can barely see. -The Grateful Dead

Re: Solar Gain Tests

Originally Posted by Barry

If I'm understanding the data correctly, by morning, they are all basically experiencing the same temp inside. Does a few degrees really make a difference in survival?

I would say most of the time no. However if that few degrees is the difference of a cluster moving to honey or not, just a couple of times in the winter it could make all the difference. I belive that last winter my survival rate would have been much better if I had wrapped my hives. The winter before and this winter I wrapped and have had far fewer colonies die out.

Re: Solar Gain Tests

That is an interesting graph, BeeCurious.
As Dean said, "The winter thermodynamics of a hive is complicated in the extreme." I'm not so sure a few degrees makes all the difference, especially in my winter climate, as well as Michael's. I keep my hives behind a building facing east. They get very little direct sun in the winter as there is another building to the south. They get protection from the prevailing weather from the west. I cant see how a piece of tar paper is going to make any difference on my hives. For hives sitting out in the middle of a field, perhaps some affect. There are just too many variables to conclude it helps or doesn't help across the board.

Re: Solar Gain Tests

Yes there are many variables involved in hive thermodynamics, but lets not make this way more complicated than it needs to be. Shinbone's test was done fairly, and the results are not surprising to me. I think doing a test using 15 roofing felt would have shown even more impressive results, maybe those kind of results are what some of you naysayers are looking for to make believers out of you.